.float {
    display: flex;
}

.float-btn {
    /* 设置形状及阴影 */
    font-size: 10px;
    width: 45px;
    height: 45px;
    -moz-user-select: none;
    -o-user-select: none;
    -khtml-user-select: none;
    -webkit-user-select: none;
    -ms-user-select: none;
    user-select: none;
    border-radius: 50%;
    background-color: white;
    box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2);
    /* 使img元素居中 */
    display: flex;
    align-items: center;
    justify-content: center;
    /* 设置按钮的位置 */
    margin: 5px;
    /* 设置过渡属性 */
    transition: width 0.5s, height 0.5s;
}

.float-btn:active {
    /* 鼠标点击时 */
    background-color: whitesmoke;
}

.float-btn:hover {
    width: 50px;
    height: 50px;
}
